Beta thalassemia major is the most severe type of beta thalassemia. Children with this disease usually develop clinical signs during their first year of life. They appear to be malnourished and may exhibit abdominal girth expansion. They show bone marrow expansion and skeletal deformations, which are a result of increased erythropoiesis due to low hemoglobin levels. A common finding is facial bone changes caused by this bone marrow expansion (sometimes referred to as Mongoloid facial features).
Other clinical signs include frequent infections, hepatomegaly, splenomegaly, gall stones, leg ulcers, iron toxicity, and poor growth and sexual development. In addition, cardiac failure due to increased burden of the heart attempting to oxygenate the tissues, can lead to serious complications and death if the condition is not treated.
In general, death usually occurs by the time these patients are in their early twenties unless treated. Lifelong blood transfusions along with iron-chelating agents are the primary treatments. Bone marrow transplantation has also been effective.
The different genotypes associated with beta thalassemia major are: B0/B0, B0/B+, or B+/B+. Beta thalassemia major is also referred to as Cooley's anemia.